Regenerative combustor cooling in a gas turbine engine

Abstract

A combustor, for a gas turbine engine, employing regenerative combustor cooling. The combustion gas flow direction extends generally longitudinally aft of the combustor fuel nozzle. A coolant flowpath between the combustor casing and the combustor liner has: 1) a longitudinally aft inlet in fluid communication with a source of compressor-derived cooling air, of lower temperature and higher pressure than diffused air from the combustor diffuser; and 2) a longitudinally forward outlet in fluid communication with the combustor fuel nozzle for "spent" cooling air to be used for combustion.

I claim: 
     
       1. A combustor for a gas turbine engine having a compressor, said combustor comprising: (a) a casing;   (b) a liner disposed proximate said casing, at least partially bounding a combustion chamber, and having generally longitudinally forward and aft portions;   (c) a fuel injector having a fuel nozzle disposed in said combustion chamber;   (d) a combustion gas flow direction in said combustion chamber extending generally longitudinally aft from said fuel nozzle;   (e) a diffuser disposed longitudinally forward of said fuel nozzle and having an inlet in fluid communication with said compressor and an outlet in fluid communication with said fuel nozzle; and   (f) a coolant flowpath between said casing and said liner having an inlet proximate said longitudinally aft portion of said liner and having an outlet proximate said longitudinally forward portion of said liner, said inlet in fluid communication with a source of cooling air with said source having an input port in fluid communication with said compressor and with said cooling air of lower temperature and higher pressure than diffused air from said diffuser, and said outlet in fluid communication with said fuel nozzle, wherein said coolant flowpath includes a shield having a portion spaced apart from and disposed between said liner and said casing, and a plate having a portion with impingement cooling holes, said plate portion spaced apart from and disposed between said liner and said shield.   
     
     
       2. The combustor of claim 1, wherein said outlet of said coolant flowpath is disposed longitudinally forward of said fuel nozzle. 
     
     
       3. The combustor of claim 1, wherein said inlet receives said cooling air between said plate and said shield. 
     
     
       4. The combustor of claim 3, wherein said liner is an imperforate liner with respect to said cooling air. 
     
     
       5. The combustor of claim 3, wherein said casing is a combustor outer casing and said liner is a combustor outer liner. 
     
     
       6. The combustor of claim 3, wherein said casing is a combustor inner casing and said liner is a combustor inner liner. 
     
     
       7. The combustor of claim 3, also including an introductory flowpath between said casing and said shield having a longitudinally forward segment including an inlet in said casing and having a longitudinally aft segment disposed longitudinally aft of said inlet of said coolant flowpath, said introductory flowpath inlet in fluid communication with said source of cooling air and said longitudinally aft segment in fluid communication with said inlet of said coolant flowpath. 
     
     
       8. The combustor of claim 7, also including a row of nozzle vanes disposed proximate said longitudinally aft portion of said liner and having an internal coolant passageway with a coolant entrance in fluid communication with said longitudinally aft segment of said introductory flowpath and a coolant exit in fluid communication with said inlet of said coolant flowpath.